Color Contact Research Articles

Photonic crystal microspheres: Synthesis, characterization, and applications in colored contact lenses

Structural colors arise from the interaction between light and ordered structural materials, making them the ideal choice for colored contact lenses. This study utilized a fast, large-scale synthesis method for silica photonic crystal microspheres, introducing carbon black to enhance the structural coloring effect. The sintering process strengthened the cohesion between particles, increasing their strength and expanding their range of applications. This approach successfully prepared SiO2 photonic crystal inks with structural colors to produce contact lenses through a pad printing technique. In particular, the coloration is solely achieved using SiO2 and carbon black without other organic species. The resulting structural color blue contact lenses exhibit high light transmittance and vivid structural colors. Furthermore, the following necessary properties were me: oxygen transmittance, visible light transmittance, hydrophilicity, and lipid and protein adsorption of the contact lenses. Cell viability experiments indicate that contact lenses made from this material are biocompatible. The results illustrated that these as-prepared lenses are promising candidates for traditional colored contact lenses.

Bacterial endocarditis caused by contact lens usage

A 17-year-old female was transferred to our hospital due to high fever, general fatigue, and dim eyesight. Three weeks before, she had used cosmetic colored contact lenses and then suffered from bloodshot eyes associated with dim eyesight. Intermittent fever and general fatigue were followed by eye symptoms. Echocardiography revealed moving vegetation on the posterior leaflet of the mitral valve associated with mild mitral valve regurgitation. There were no infectious sites in systemic examinations; thus, the cause of infective endocarditis was considered the infection due to contact lens usage. The patient initially received mitral valve plasty associated with the removal of infective sites. However, redo surgery was necessary 19 days later due to the relapse of infection, and the mitral valve was replaced by bioprosthesis. Traumatic injury of vessels due to inappropriate contact lens usage seemed to lead to systemic hematogenous infection and subsequent endocarditis. We report a rare case of infective endocarditis which was caused by contact lens usage.

Center Deviation Measurement of Color Contact Lenses Based on a Deep Learning Model and Hough Circle Transform.

Ensuring the quality of color contact lenses is vital, particularly in detecting defects during their production since they are directly worn on the eyes. One significant defect is the "center deviation (CD) defect", where the colored area (CA) deviates from the center point. Measuring the extent of deviation of the CA from the center point is necessary to detect these CD defects. In this study, we propose a method that utilizes image processing and analysis techniques for detecting such defects. Our approach involves employing semantic segmentation to simplify the image and reduce noise interference and utilizing the Hough circle transform algorithm to measure the deviation of the center point of the CA in color contact lenses. Experimental results demonstrated that our proposed method achieved a 71.2% reduction in error compared with existing research methods.

A Study on Functional Color Contact Lens Materials Including Gallate Group Additives

A Study on Functional Color Contact Lens Materials Including Gallate Group Additives

Colored contact lens with all-weather humidity-triggered discoloration

Developing versatile printing inks with good biocompatibility is essential for the fabrication of functional colored contact lenses. In this work, by employing a new kind of printing ink that shows humidity-induced discoloration, multifunctional colored contact lenses have been constructed. The obtained products have displayed distinct and stable all-weather humidity-triggered discoloration under ambient conditions. More importantly, combined with a smartphone, the quantitative and qualitative relationship between the discoloration of colored contact lenses and environmental humidity has been established, which is expected to realize the early prediction of humidity-related eye diseases in a portable, economical, and in-situ manner.

A Deep Learning Technique for Optical Inspection of Color Contact Lenses

Colored contact lenses have gained popularity in recent years. However, their production process is plagued by low efficiency, which is attributed to the complex nature of the lens color patterns. The manufacturing process involves multiple complex steps that can introduce defects or inconsistencies into the contact lenses. Moreover, manual inspection of a considerable number of contact lenses that are produced inefficiently in terms of consistency and quality by humans is prevalent. Alternatively, automatic optical inspection (AOI) systems have been developed to perform quality-control checks on colored contact lenses. However, their accuracy is limited due to the increasing complexity of the lens color patterns. To address these issues, convolutional neural networks have been used to detect and classify defects in colored contact lenses. This study aims to provide a comprehensive guide for AOI systems using artificial intelligence in the colored contact lens manufacturing process, including the benefits and challenges of using these systems. Further, future research directions to achieve a classification accuracy of >95%, which is the human recognition rate, are explored.

A novel transconjunctival, intrascleral, ab-externo, knotless, and double-flanged technique with 6-0 Prolene for iridodialysis repair

Small traumatic iridodialysis (ID) may be asymptomatic, but large ones usually cause polycoria and corectopia, leading to symptoms like diplopia, glare, and photophobia. The management of ID, including medical and surgical methods, depends upon the patient’s symptoms. Mild glare and diplopia can be treated either with atropine, antiglaucoma medications, tinted spectacles, colored contact lens, or corneal tattooing, but extensive IDs require surgical options. The surgical techniques are challenging due to the iris texture and the damage encountered during the primary surgery, the narrow anatomical workspace for repair, and the associated surgical complications. Numerous techniques have been described by several authors in the literature; each has its advantages and disadvantages. All the procedures described previously involve conjunctival peritomy, scleral incisions, and suture knots and are time consuming. Here, we report a novel transconjunctival, intrascleral, knotless, and ab-externo, double-flanged technique for repair of large ID with a 1-year follow-up.

Fabrication of 3D‐Printed Contact Lenses and Their Potential as Color Blindness Ocular Aids

AbstractColor blindness or color vision deficiency (CVD) is a congenital ocular deficiency that hampers patients’ daily life activities. CVD patients rely mostly on using wearable visual aids that enhance color distinction by blocking problematic wavelengths of light. Contributing to that, this study examines the fabrication of 3D‐printed colored contact lens for color blindness management. A vat photopolymerization based 3D printing technology is utilized to fabricate the contact lenses for CVD patients. An in‐house prepared resin is mixed with a low‐cost colored ink to attain the desired blocking range (520–580 nm). The fabricated lens blocks more than 50% of light at the problematic wavelengths, along with exhibiting minimal leakage when stored and examined in water and contact lens storage solution. Average contact angle and water content values are 48° and 56%, respectively. Mechanical properties demonstrate the physical adequacy of the contact lens. The CVD filtering efficacy of the tinted contact lens and its potential as a CVD wearable is evaluated by comparing its optical performance with that of commercial products. Finally, cytotoxicity analysis of the lens to dermal fibroblast cells reveals the biocompatibility of the lens as the cell viability remains greater than 75% after 24 h.

Novel SiO2 photonic crystal microspheres as inorganic pigments for structural color contact lenses

Traditional contact lenses patterns are mostly colored with organic pigments, but they suffered a pigment leakage risk after long-term wearing, which causes corneal inflammation and ulceration. To solve this issue, the structural color is applied to contact lenses because it has color and pigment free. Herein, we reported the application of SiO2 photonic crystal microspheres in contact lenses. We successfully prepared SiO2 photonic crystal ink with structural color and fabricated contact lenses by ink transfer printing, and these contact lenses also contain patterns and pupil areas that are the same as the traditional pigment one. In addition, in vitro cytotoxicity test, physicochemical property test, and optical property test were carried out to verify the performance of the prepared structural color lenses. All results suggested it has great potential to replace traditional organic pigment contact lenses.

Visual Field Parameters and Pupil Size Measured through and Compared between Colored Contact Lenses and Clear Contact Lenses: A Prospective Comparative Pilot Study in Asian Population

Objective: To compare visual field (VF) parameters and pupil size as measured through colored and clear contact lenses (CL) in Asian population.Materials and Methods: Demographic data and CL prescription data were recorded during the baseline visit. Visual acuity and autorefraction were evaluated while patients wore clear CL, followed by slit-lamp examination and intraocular pressure measurements after CL removal. During the second visit, subjects were given dark browncolored CL with their same prescription. Visual acuity and autorefraction were measured. Pupil size and VF tests were measured twice with the clear CL and the colored CL. Measurements through colored and clear CL were compared.Results: Twenty-one volunteers (mean age: 31 years) were recruited. Refractive error varied from 0.00 to -7.00 diopters. Mean horizontal meridian measured through clear and colored CL was 134.8±7.8° and 133.3±4.7°, respectively. Mean vertical meridian measured through clear and colored CL was 100.1±3.8° and 100.4±2.5°. Mean total VF area measured through clear and colored contact lenses was 9,890.9±822.8° and 9,882.7±528.1°. There was no significant difference between clear and colored CL groups for horizontal meridian, vertical meridian, total VF area, or pupil size.Conclusion: There was no significant difference in any evaluated parameters between clear and colored CL.

Electrochromic soft contact lenses with built-in non-interfering, high-efficient dual-band wireless power transfer system

Color contact lenses attracts considerable attention for vision management and cosmetic applications nowadays. However, they require a wired power supply system because positive and negative voltages need to be applied for color modulation of electrochromic coating on the lens. This study demonstrates a wireless-powered electrochromic soft contact lens that modulates color using a dual-band wireless power transfer (WPT) system. The stretchable and conductive electrochromic film is the result of fabrication by spin-coating a mixed solution comprising PEDOT:PSS for the electrical conductor, polyurethane for the stretchable supportive layer, ethylene glycol, and dodecylbenzene sulfonic acid as conductivity enhancers. The dual-band system for negative voltage at 13.56 MHz and positive voltage at 28.4 MHz consists of two resonators using semi-loop antennas connected in parallel with capacitors. The dual-band resonators and electrochromic films are electrochemically bonded onto a commercially available soft contact lens. The proposed lens is capable of reversibly and wirelessly modulating the color from transparent to dark blue for several tens of seconds and usable as wireless color filters and Morse code transmitters.

Large irides enhance the facial attractiveness of Japanese and Chinese women

Since large eyes are often perceived to enhance facial attractiveness, many individuals are motivated to change their eyes' appearance. Colored contact lenses are often used by young women to darken the limbal rings of their irides, to increase their facial attractiveness. Among Westerners, wearing contact lenses with limbal rings enhances facial attractiveness; a similar effect might exist for East Asians whose irides are darker; although, the mechanism underlying these preferences in Westerners and East Asians might differ. In this study, we investigated whether larger irides increased the attractiveness of Japanese and Chinese women, and whether this effect was accompanied by changes in perceived friendliness or youthfulness. We manipulated eye size by enlarging only the iris or the whole eye, and asked participants to rate face stimuli in terms of facial attractiveness, friendliness, and youthfulness. We found that larger irides enhanced not only attractiveness but also perceived youthfulness and friendliness, and that there was a significant correlation between attractiveness and friendliness. Further, iris-enlarged faces were perceived as more attractive even when the iris was originally dark, as enlarged dark irides were confused with dilated pupils, which are often perceived as a sign of attraction.

Soliloquy of Colored Contact Lenses

Soliloquy of Colored Contact Lenses

Implications of inherited color vision deficiency on occupations: A neglected entity!

Purpose:To highlight the plight of individuals with congenital color vision deficiency (CVD).Methods:This is a retrospective study in which 191 electronic medical records of individuals with the diagnosis of inherited CVD, who visited the eye institute, between January 2010 and January 2021 were included. The inclusion criteria included diagnosis based on the failure in pseudoisochromatic plates (Ishihara / Hardy, Rand and Rittler (HRR) and age range between 18 and 35 years. The patient’s medical history, age, gender, type of defect, and preference for colored contact lenses was noted. Medical records were excluded if the participant had any other ocular pathology apart from congenital CVD.Results:At least 30% (57/191) of the individuals explicitly requested for color vision examination for a job-related purpose. Amongst them, the most common jobs aspired were army (~25%; [14/57]) followed by police (21%; [12/57]). There was only 2.6% (5/191) of individuals in which the type of CVD (protan/deutan) was classified. Only 5.2% of them (10/191) sought an X-Chrome contact lens trial.Conclusion:This study reported the occupational setbacks experienced by individuals with CVD. This study highlights the need to identify CVD at a younger age, thereby avoiding occupational-related setbacks later in life.

Effect of Contact Lenses on Contrast Sensitivity under Various Lighting Conditions.

PurposeTo assess contrast sensitivity in clear and colored soft contact lenses under different lighting conditions.MethodsThis study was performed on 34 medical students. Visual acuity was measured using a tumbling E chart at a distance of 6 m, and contrast sensitivity was determined by Pelli Robson chart at a distance of 1 m. These tests were repeated in mesopic (3 lux) and glare (2000 lux) conditions. Then, a clear contact lens was applied to one eye and a colored contact lens was applied to the other. After 2 hr, visual acuity and contrast sensitivity were measured for each individual. The results were compared with and without contact lenses under normal, mesopic, and glare conditions.ResultsThe mean refractive error was 0.44 0.20 diopters. Repeated measures ANOVA showed a decline in contrast sensitivity with colored and clear contact lenses as compared to no-lens condition (P 0.001). Additionally, lighting conditions had a significant impact on contrast sensitivity (P 0.001); contrast sensitivity was lower in mesopic and glare conditions than under normal lighting condition.ConclusionIn addition to the drop in contrast sensitivity under unusual lighting conditions (e.g., glare and mesopic), wearing soft contact lenses can further reduce contrast sensitivity in different lighting conditions. Therefore, people who wear contact lenses should be aware of this reduction in visual performance in conditions like driving at night or in the fog.

Visual Inspection of Non-Prescription Monthly Colored Contact Lenses: Safety Issues for Contact Lens Wearers

Objective: To survey the prevalence of non-prescription monthly colored contact lenses (CL) defects in an electronicmarketplace (e-marketplace) in Thailand using visual inspection (VI).Materials and Methods: This cross-sectional study included the 252 items listed from 23 online shops in ane-marketplace in Thailand during April 2021. Online customer reviews for each shop were examined and complaintsregarding colored CL product defects, delivery, services and abnormal symptoms after use were collected. Productpacking and visible internal and external product characteristics were visually inspected under sufficient light forthe prevalence of defects by three examiners.Results: Sixteen out of twenty-three online shops (69.57%) had customer complaints. Wrong delivery was the mostcommon complaint (60.87%). Five characteristics of product defects were described by customers, of which abnormalscratches/marks on CL (8.70%) was the most common. Abnormal symptoms after use were found in 43.84% of theshops. Two hundred and thirty-seven pairs of colored CL (94.05%), 470 vials and four blisters from 19 shops wereexamined. Defective products were found to be 8.02%. The most common visible external and internal productdefects were dirty products (3.80%) and foreign bodies in the original sealed manufacturer’s containers (1.90%),respectively. Other defects, e.g. scratched or peeling label, incompletely closed aluminum cap, surface wear of CL,abnormal scratches or marks on CL and immobility of CL in solution were also found.Conclusion: Non-prescription monthly colored CL in the e-marketplace have many visible defective characteristicsthat CL wearers should be concerned about. This study suggests that VI of CL products before use may be animportant potential safety factor for CL wearers.

Experience of applying cosmetic Etafilcon A contact lens in cases with microcornea.

Microcornea is a rare condition that frequently resulets in serious cosmetic concerns due to the resultant asymmetrical appearance of the eye, and its cosmetic rehabilitation is possible with the use of colored contact lenses. This paper aims to present our experiences with the use of cosmetic Etafilcon A contact lenses for microcornea. Eight patients with unilateral microcornea without any systemic involvement were included in this study, and they underwent routine ophthalmological examination, corneal topography, and optical biometry. We applied the cosmetic Etafilcon A contact lens (1-DAY ACUVUE® DEFINE® with Lacreon®) of the same edge color to the patients. The levels of satisfaction in terms of cosmesis and comfort were evaluated with the use of visual analog scales (VAS). In the patients, the corneal diameter asymmetry was acceptably adjusted, and each of the patients reported extreme satisfaction. The mean VAS score was 8.9 ± 1.0 (range: 7-10) for the cosmetic satisfaction rate and 8.4 ± 1.0 (range: 7-10) for the comfort rate. The patients obtained the best-corrected visual acuity without or with additional eye-glasses. None of the patients complained about vision issues under photopic and scotopic conditions. 1-DAY ACUVUE® DEFINE® with Lacreon® lens has promising satisfactory cosmetic outcomes along with visual enhancement in cases of microcornea. This is the first study to report the use of this lens for the cosmetic rehabilitation of patients with microcornea.

A Review of the Evidence and the Early History of Colored Contact Lenses

A Review of the Evidence and the Early History of Colored Contact Lenses

Intrastromal Corneal Ring Segments Implantation and Descemet Membrane Endothelial Keratoplasty for Coexisting Keratoconus and Fuchs Endothelial Dystrophy.

To report two cases of coexisting keratoconus and Fuchs endothelial dystrophy treated with intrastromal corneal ring segments (ICRS) implantation and Descemet membrane endothelial keratoplasty (DMEK). Two patients with coexisting keratoconus and Fuchs endothelial dystrophy underwent ICRS implantation and DMEK, in a two-stage procedure. Follow-up evaluation included Scheimpflug tomography and optical coherence tomography. In both cases, ICRS implantation improved corneal topography and DMEK restored normal corneal thickness. Corrected distance visual acuity improved from 20/100 to 20/30 and from 20/60 to 20/25. Urrets-Zavalía syndrome was diagnosed in one case and addressed with colored contact lens fitting. Low vision resulting from coexisting keratoconus and Fuchs endothelial dystrophy might be addressed more selectively with posterior lamellar keratoplasty and ICRS implantation. Urrets-Zavalía syndrome must be considered a possible complication after DMEK, especially in patients with keratoconus. [J Refract Surg. 2020;36(10):703-706.].

A Study on the Spectral Transmittance of UV-Blocking Contact Lenses

Purpose : The purpose of this study was to measure the spectral transmittance of domestic hydrogel contact lenses, and to find out if they meet the standards of visible light and UV-blocking spectral transmittance. Methods : Hydrogel contact lenses including UV-blocking contact lenses were randomly selected in this study. The range of spectral transmittance measurement in the experimental lenses was set to visible light, UV-A and UV-B. Visible light transmittance was based on ANSI Z80.20:2004. And the UV spectral transmittance was compared to the UV-blocking contact lenses standards applied by the International Organization for Standardization (ISO) and the Food and Drug Administration (FDA). UV-blocking contact lenses were classified as Class 1 and Class 2 according to the standards. Results : As a result of measuring visible light transmittance of 14 types of experimental lenses, 4 transparent contact lenses showed 88% or less, but did not deviate significantly from the range. And all 7 types of color contact lenses were measured to be over 70% and met the standards. In the spectral transmittance of UV, the UD-4, 5, 6 lenses among the 10 types of UV-blocking contact lenses showed the range of a spectral transmittance of 86.67~88.59% and 82.41~83.47% for UV-A and UV-B, respectively. These UV wavelength values were found to be non-compliant with ISO and FDA UV-blocking standards. Conclusion : It shows that some UV-blocking contact lenses do not meet ISO and FDA UVblocking standards, and they were all domestic products.